Electrohydraulic control arrangements have been increasingly used in the field of engineering. The reason therefor is the possibility of providing the control part of a control chain to be of an electrical configuration and the energy part of the control chain to be of a hydraulical configuration. The electromagnetically actuated hydraulic valves represent the points of connection between electric and hydraulic components. These valves are combined to form assembly groups or. These assembly groups include hydraulic inlet and outlet lines and of one or more outgoing cables. The cables incorporate electrical lines for the control signals for switching the electromagnetic valves, that is for energizing the coils of the solenoid valves.
Systems of this type are described in German patent application P37 42 830.6. This patent application describes a valve block assembly composed of one or more electromagnetically actuatable hydraulic valves (solenoid valves), a valve cover, and a power-supply means for energizing the coils of the solenoid valves.
The special feature of the valve block assembly of this patent application resides in that there is provision of a printed circuit board which, as a construction unit, can be mounted on all electrical contacts of the coils, which comprises electrical conducting paths that establish the electric connections between the coils and an outgoing cable of the valve block. The circuit board for the outgoing cable includes a contact device which is common to all conducting paths and which is arranged so that the dismountable plug contact plug of the connecting cable can be plugged directly on the circuit board which forms part of the contact device.
German patent application P 37 01 019.0 depicts a valve block for a slip-controlled hydraulic brake system comprising a valve-receiving member accommodating several solenoid valves, a frame, a cover closing the frame and a plug assembly containing a plurality of contact blades, the solenoid valves being coupled to the contact blades by a contacting foil. The special characteristic of this valve block is that the frame is designed integrally with the cover and the plug assembly in such a fashion that a one-part cover unit is formed which permits soldering the contacting foil and is fixed on the valve-receiving member in a sealed manner.
Arrangements of the this type composed of a valve block and an associated cover entail the following problems in practice: Difficulties occur when the mounting cover on the valve block by machine. Automatic mounting is possible only in a very intricate fashion. The automatized assembly of valve block and cover present centering and sealing problems. Further, securing and sealing of the electrical lines for the coils of he solenoid valves introduces additional problems.